Calculate the Fibonacci number (recursive approach) in compile time (constexpr) in C++11

Question

I wrote the program Fibonacci number calculation in compile time (constexpr) problem using the template metaprogramming techniques supported in C++11. The purpose of this i

Answer 1

The reason is that your runtime solution is not optimal. For every fib number, functions are called several times. The fibonacci sequence, has overlapping subproblems, so for example fib(6) calls fib(4), and fib(5) also calls fib(4).

The template based approach, uses (inadvertently) a Dynamic Programming approach, meaning that it stores values for previously calculated numbers, avoiding repetition. So, when fib(5) calls fib(4), the number was already calculated when fib(6) did.

I recommend looking up "dynamic programming fibonacci" and trying that, it should speed things up dramatically.